The standard process for manufacturing microneedles containing API requires a way to process the API, including dissolving the API in a co-solvent and a drying process. In this study, the authors introduce a novel microneedle system that involves physically attaching API particles to the biocompatible adhesive surface of the microneedles. To manufacture particle-attached microneedles, an adhesive surface was prepared by coating polydimethylsiloxane (PDMS) mixed with an elastomer base and a curing agent at a ratio of 40:1 (PDMS40) onto polylactic acid microneedles (PLA), and then attaching ovalbumin (OVA) particles with a mean diameter of 10 μm to the PDMS adhesive layer. The OVA particles were delivered for 5 min into porcine skin with a delivery efficiency of 93% ex vivo and into mouse skin with a delivery efficiency of over 90% in vivo. Finally, mouse experiments with OVA particle-attached microneedles showed a value of OVA antibody titer similar to that produced by intramuscular administration. Particle-attached microneedles are a novel microneedle system with a dry coating process and rapid API delivery into the skin. Particle-attached microneedles can provide a wide range of applications for administering drugs and vaccines.
Keywords: Dry coating; Particle-attached microneedles; Physical attachment; Polydimethylsiloxane; Rapid delivery.
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